Identification of nif genes in N₂‐fixing bacterial strains isolated from rice fields along the Yangtze River Plain

Abstract

The aim of this research was to identify nifH and nifHDKYE ' genes in twenty strains of N2-fixing heterotrophic bacteria isolated from rice fields in the Yangtze River Plain. Southern hybridization of the total DNA from each strain was performed with the Klebsiella pneumoniae nifHDKYE ' gene probe (6.2 kb Eco RI fragment from pSA30) and the Azospirillum brasilense nifH gene probe (0.6 kb Eco RI-Hin dIII fragment from pHU8). We found that Eco RI fragments of total DNA from Aeromonas hydrophila HY2, Bacillus azotoformans FD, Bacillus licheniformis NCH1, NCH5, WH4, Bacillus brevis NC2, Bacillus pumilus NC12, Bacillus cereus NCH2, Citrobacter freundii HY5, HY9, Derxia gummosa HZ5, Pseudomonas mendocina HZ1 and Pseudomonas pseudoalcaligenes WH3 were positively hybridized with both of the probes. Agrobacterium radiobacter HY17, Corynebacterium sp. HY12, YZ and Pseudomonas sp. HY11 had Eco RI fragments hybridized with the K. pneumoniae nifHDKYE ' gene probe. An Eco RI fragment of total DNA from Bacillus megaterium YY4 was positively hybridized to the A. brasilense nifH gene probe. No hybridization sign was found in the total DNA fragments from Alcaligenes cupidus YY6 and Corynebacterium sp. NC11 hybridized with either of the gene probes. The data provide the number and size of EcoRI fragments of the total DNA hybridized with the nif gene probes for these strains of rarely studied species, suggesting additional evidence for N2 fixing and nif gene diversity of N2-fixing bacteria in rice fields along the Yangtze River Plain.

Density and diversity of diazotrophic bacteria isolated from Amazonian soils using N-free semi-solid media

“…In the phylum Firmicutes, isolates UFLA85 and UFLA94 were more similar to Bacillus subtilis, with 99 % and 97 % 16S rDNA sequence similarity, respectively; additionally, UFLA75 was more similar to B. cereus and B. thuringiensis, with 94 % sequence similarity. The genus Bacillus is also known to have nitrogen-fixing species, including B. cereus and B. subtilis (Xie et al, 1998;Ding et al, 2005;Xie et al, 2006). In our study, all Bacillus isolates exhibited acetylene reduction indicating the presence of nitrogenase.…”

Bacillus simplex—A Little Known PGPB with Anti-Fungal Activity—Alters Pea Legume Root Architecture and Nodule Morphology When Coinoculated with Rhizobium leguminosarum bv. viciae

“…We did not find any evidence for nifH in B. simplex 30N-5 despite the fact that we based our primer set on data from [41] and that several reports were published earlier regarding nifH presence in various Bacillus genomes [41][42][43]. We also found no evidence for nif genes in an analysis of a draft sequence of the B. simplex genome.…”

Diversity of plant growth-promoting bacteria associated with sugarcane

“…Thus, the discovery of Bacillus hosted in the shoot of sugarcane open several possibilities to promote plant growth with this genus. These bacteria present high genetic diversity and agricultural relevance (McSpadden Gardener, 2004), mainly for presenting nitrogenase activity in some species, such as B. subtilis, B. pumilus, and B. megaterium (Xie et al, 1998). A previous study has reported that many species of Bacillus can contribute significantly to the plant growth (Davolos et al, 2015).…”